1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to switching a channel, and image display devices which switch channels More particularly, the present invention relates to a method for switching a channel using existing navigation keys of an image display device providing a broadcast from multi-channels, and an image display device which implements said method.
2. Description of the Related Art
Image display devices display images that are received externally through an antenna. More specifically, if a user selects a desired channel, an image display device is tuned to the selected channel and displays images to be viewed by the user that are received from the channel through an antenna. Generally, image display devices include, for instance, mobile phones, personal digital assistants (PDAs) and television sets (TVs).
Recently, as the broadcasting environment has been digitalized and moving image compression technology has been developed, a frequency band of 6 MHz, which is allocated to one TV channel in an analog broadcasting environment, is set aside for one channel of high definition (HD) quality. Accordingly, terrestrial waves and cable broadcasting stations tend to provide multimode services (MMS) by adding up to six channels, such as a channel of standard definition (SD) quality, an audio channel, a data channel, into the rest of the frequency band.
Consequently, digital TVs (DTVs), as one example of an image display device, provide multiple services and increase the number of viewable channels sharply.
However, as the number of channels increases, conventional image display devices take a longer time to switch channels using up/down keys. That is, a channel of HD quality (referred to hereinafter as a “major channel”) and other channels (referred to hereinafter as “minor channels”) are transmitted in a frequency band for one channel by multi-channel broadcasting, so that the number of channel switches between major channels, between major channels and minor channels, and between minor channels are increased.
For example, if it is assumed that a currently viewed major channel is 7-1, there may be minor channels 7-2, 7-3, 7-4 and 7-5, and the next major channel is 8-1. If a user wants to switch to the next major channel 8-1, the user must manipulate the keys 5 times in a related art image display device.
That is, the current major channel 7-1 is switched through channels 7-2, 7-3, 7-4 and 7-5 to the channel 8-1 by pressing an up/down key 5 times.
Therefore, according to the related art channel switching method using up/down keys in a multi-channels environment, it takes a long time for users to select a desired channel, and user inconvenience due to an increased key pressing occurs.
Moreover, as a user does not know how many minor channels that a major channel has, the user must manipulate the up/down keys blindly to switch to a subsequent major channel, resulting in greater user inconvenience.